Curling iron



FIG. 1 is a top perspective view of a curling iron showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a side elevational view thereof, the side opposite being a mirror image of the side shown;

FIG. 4 is a top plan view thereof;

FIG. 5 is a bottom plan view thereof; and

FIG. 6 is a rear elevational view thereof. 

The ornamental design for a curling iron, as shown and described. 